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bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine
From: |
Rob Browning |
Subject: |
bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine |
Date: |
Mon, 16 Jul 2012 21:33:58 -0500 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) |
Rob Browning <rlb@defaultvalue.org> writes:
> Glenn Morris <rgm@gnu.org> writes:
>
>> But why does (abs 8.0) return an arithmetic error at all...?
>
> OK, at the moment, I believe the short answer is because fabs() is
> changing errno which triggers the default clause in IN_FLOAT() here:
>
> default: arith_error (float_error_fn_name, float_error_arg);
>
> I've been told that this should be considered an Emacs bug because the
> effect of fabs() on errno is strictly undefined, and so fabs() is within
> its rights to do whatever it wants to the value.
For now, I'm going to deploy a patch in the Debian package that just
adds a DEB_IN_FLOAT_NOERRNO() that omits the errno checking, and then
uses that macro for the fabs() call.
Doing something with a similar result would probably be advisable.
Thanks for the help.
--
Rob Browning
rlb @defaultvalue.org and @debian.org
GPG as of 2002-11-03 14DD 432F AE39 534D B592 F9A0 25C8 D377 8C7E 73A4
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, (continued)
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Rob Browning, 2012/07/13
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Eli Zaretskii, 2012/07/14
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Glenn Morris, 2012/07/13
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Eli Zaretskii, 2012/07/13
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Glenn Morris, 2012/07/13
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Eli Zaretskii, 2012/07/13
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Andreas Schwab, 2012/07/13
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Rob Browning, 2012/07/14
- bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine,
Rob Browning <=
bug#11913: Unusual Emacs 24.1 arithmetic error (abs) on i386 machine, Paul Eggert, 2012/07/16